1. Field of the Invention
The present invention relates to an injector test stand for fuel injectors.
2. Description of the Related Art
For the clamping of fuel injectors for high-pressure accumulator injection systems, for example the common rail injection system, in injector test stands, several options for chucking the fuel injectors to be tested in the injector test stands are available, which are dependent on the sealing of the fuel injector with respect to an injection chamber that is positionable on the test stand. It is possible to seal the fuel injectors, in each case accommodated in the injector test stand, in the radial direction in the injection chamber, or to bring about sealing in the axial direction.
For radial sealing in the nozzle area of the fuel injector, fixing the fuel injector in the upper area inside the injector test stand is generally sufficient, since in this case no axial force occurs. The fuel injector is fixed in the upper area by, for example, simply clamping the fuel injector to a test pressure line which acts with system pressure on the test piece which is chucked to the injector test stand. Other designs provide for clamping the fuel injector at its injector body with the aid of a slotted round socket or vise-like clamping jaws having a V-shaped cutout.
For axial sealing of the fuel injector, which generally occurs at the nozzle clamping nut of the fuel injector and which represents the same mounting position as the subsequent position in the motor vehicle, i.e., on the internal combustion engine, the necessary sealing force on the mounting in the axial direction must be applied in the opposite direction. The fuel injector is tensioned downwardly at its spanner flat, for example at the nozzle clamping nut, or the necessary counterforce is also applied at that location. For pushing the fuel injector down over the clamping surface in the axial direction, an injector-specific clamping claw is generally mounted in a holder, and the fuel injector is pushed down, against the axial seal, via the tightening of the clamping claw.
In many cases, an injection chamber which generally has a positionable design is used on injector test stands, and is pressed against the fuel injector by pneumatic means or via a tightening thread and held against the spanner flat. The mounting of the injection chamber which is displaceably held, i.e., variably positionable, on the injector test stand is generally achieved with the aid of different adapters or mounting plates which have an injector-specific design and are fastened to the injector test stand.
All of the proposed injector test stands in each case require injector-specific mounting plates, adapters, or clamping devices corresponding to the number of variants of the test pieces to be tested on an injector test stand, i.e., corresponding to the number of variants of the fuel injectors to be tested, which represents a highly unsatisfactory situation.